Baked products such as bread are prepared from a dough which is usually made from the basic ingredients (wheat) flour, water and optionally salt. Depending on the baked products, other ingredients added may be sugars, flavours etceteras. For leavened products, primarily baker's yeast is used next to chemical leavening systems such as a combination of an acid (generating compound) and bicarbonate.
In order to improve the handling properties of the dough and/or the final properties of the baked products there is a continuous effort to develop processing aids with improving properties. Processing aids are defined herein as compounds that improve the handling properties of the dough and/or the final properties of the baked products. Dough properties that may be improved comprise machineability, gas retaining capability, reduced stickiness, elasticity, extensibility, moldability etcetera. Properties of the baked products that may be improved comprise loaf volume, crust crispiness, crumb texture and softness, flavour relative staleness and shelf life. These dough and/or baked product improving processing aids can be divided into two groups: chemical additives and enzymes (also referred to as baking enzymes).
Yeast, enzymes and chemical additives are generally added separately to the dough. Yeast may be added as a liquid suspension, in a compressed form or as active dry (ADY) or instant dry yeast (IDY). The difference between these yeast formulations is the water- and yeast dry matter content. Liquid yeast has a yeast dry matter content of less than 25% (w/v). Cream yeast is a particular form of liquid yeast and has a dry matter content between 17 and 23% (w/v). Compressed yeast has a yeast dry matter content between 25-35% (w/v) while the dry yeast formulations have a yeast dry matter content between 92-98% (w/v).
Enzymes may be added in a dry, e.g. granulated form or in liquid form. The chemical additives are in most cases added in powder form. Also, processing aid compositions which are tailored to specific baking applications, may be composed of a dedicated mixture of chemical additives and enzyme.
The preparation of a dough from the ingredients and processing aids described above is well known in the art and comprises mixing of said ingredients and processing aids and one or more moulding and fermentation steps.
The preparation of baked products from such doughs is also well known in the art and may comprise molding and shaping and further fermentation of the dough followed by baking at required temperatures and baking times.
Chemical additives with improving properties comprise oxidising agents such as ascorbic acid, bromate and azodicarbonate, reducing agents such as L-cysteine and glutathione, emulsifiers acting as dough conditioners such as diacetyl tartaric esters of monoldiglycerides (DATEM), sodium stearoyl lactylate (SSL) or calcium stearoyl lactylate (CSL), or acting as crumb softeners such as glycerol monostearate (GMS) etceteras, fatty materials such as triglycerides (fat) or lecithin and others.
As a result of a consumer-driven need to replace the chemical additives by more natural products, several baking enzymes have been developed with dough and/or baked product improving properties and which are used in all possible combinations depending on the specific baking application conditions. Suitable enzymes include starch degrading enzymes, arabinoxylan- and other hemicellulose degrading enzymes, cellulose degrading enzymes, oxidizing enzymes, fatty material splitting enzymes, protein degrading, modifying or crosslinking-enzymes.
Starch degrading enzymes are for instance endo-acting enzymes such as alpha-amylase, maltogenic amylase, pullulanase or other debranching enzymes and exo-acting enzymes that cleave off glucose (amyloglucosidase), maltose (beta-amylase), maltotriose, maltotetraose and higher oligosaccharides.
Arabinoxylan- and other hemicellulose degrading enzymes are for instance xylanases, pentosanases, hemicellulase, arabinofuranosidase, glucanase and others.
Cellulose degrading enzymes are for instance cellulase, cellobiohydrolase and beta-glucosidase.
Oxidizing enzymes are for instance glucose oxidase, hexose oxidase, pyranose oxidase, sulfhydryl oxidase, lipoxygenase, laccase, polyphenol oxidases and others.
Fatty material splitting enzymes are for instance lipolytic enzymes such as triacylglycerol lipases, phospholipases (such as A1, A2, B, C and D) and galactolipases.
Protein degrading, modifying or crosslinking enzymes are for instance endo-acting proteases (serine proteases, metalloproteases, aspartyl proteases, thiol proteases), exo-acting peptidases that cleave off one amino acid, or dipeptide, tripeptide etceteras from the N-terminal (aminopeptidases) or C-terminal (carboxypeptidases) ends of the polypeptide chain, asparagines or glutamine deamidating enzymes such as deamidase and peptidoglutaminase or crosslinking enzymes such as transglutaminase.
Baking enzymes may conveniently be produced in microorganisms. Microbial baking enzymes are available from a variety of sources; Bacillus spec. are a common source of bacterial enzymes, whereas fungal enzymes are commonly produced in Aspergillus spec.
Baking enzymes may be used in a manifold of baked goods. The term “baked goods” is herein defined as to comprise bread products such as tin bread, loaves of bread, French bread as well as rolls, cakes, pies, muffins, yeast raised and cake doughnuts and the like.
In the above processes, it is advantageous to use baking enzymes that are obtained by recombinant DNA techniques. Such recombinant enzymes have a number of advantages over their traditionally purified counterparts. Recombinant enzymes may be produced at a low cost price, high yield, free from contaminating agents like bacteria or viruses but also free from bacterial toxins or contaminating other enzyme activities.